7. The lower extremities.pdf anatomy pdf

the lower extremities
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pelvis-regional anatomy
Pelvic Regions
• False (Greater) Pelvis:
• Superior region
• Part of the abdominal cavity
• True (Lesser) Pelvis:
• Inferior region
• Encloses the pelvic cavity

Pelvic Brim
The pelvic brim is the bony boundary that forms the upper edge of the pelvic inlet.
It marks the transition between the greater (false) pelvis and the lesser (true) pelvis.
Bony Landmarks of the Pelvic Brim
• Sacral Promontory: The anterior projection of the first sacral vertebra.
• Arcuate Lines of the Ilium: Curved ridges on the inner surface of the iliac bones.
• Pectineal Line: A ridge on the superior ramus of the pubis.
• Pubic Symphysis: The joint where the two pubic bones meet
Anatomical Boundaries:
• Anteriorly: Pubic symphysis and pectineal line.
• Laterally: Arcuate lines of the ilium.
• Posteriorly: Sacral promontory.

Borders of the True and False Pelvis
False Pelvis (Major Pelvis)
• Anterior Border: Abdominal wall muscles (mainly the lower part of the
anterior abdominal wall).
• Lateral Borders: Iliac bones (iliac fossa).
• Posterior Border: Lumbar spine.
True Pelvis (Minor Pelvis)
• Anterior Border: Pubic symphysis and pubic bones.
• Lateral Borders: Ischial bones and ischial spines.
• Posterior Border: Sacrum and coccyx.

Pelvic Cavity
The pelvic cavity is a bowl-shaped
structure located in the true pelvis,
which is the inferior region of the
pelvis.
Location:
• Continuous with the abdominal cavity
above.
• Enclosed by the pelvic bones, forming
the boundaries of the true pelvis.

Pelvic Cavity in Males
• Urinary System:
• Bladder: Located in the lower part of the pelvic cavity.
• Urethra: Passes through the prostate and extends to the external genitalia.
• Reproductive System:
• Prostate Gland: Located below the bladder, surrounding the urethra.
• Seminal Vesicles: Located near the base of the bladder and contribute to the production of
semen.
• Vas Deferens: The duct that carries sperm from the testes to the urethra.
• Digestive System:
• Rectum: Located in the posterior part of the pelvic cavity.
• Part of the Colon: Specifically, the sigmoid colon lies in the pelvic cavity.
• Vascular Structures:
• Pelvic Blood Vessels: The internal iliac arteries and veins, as well as other smaller vessels, supply
blood to the pelvis.
• Nerves: The sacral and coccygeal nerves provide innervation to the pelvic organs.

Pelvic Cavity in Females
• Urinary System:
• Bladder: Similar to males, located in the lower part of the pelvic cavity.
• Urethra: Passes from the bladder to the external genitalia.
• Reproductive System:
• Uterus: Located in the center of the pelvic cavity, between the bladder and rectum. It consists of the body,
cervix, and endometrial lining.
• Ovaries: Located on either side of the uterus, responsible for producing eggs and hormones.
• Fallopian Tubes: Extend from the uterus to the ovaries and are the pathways through which eggs travel.
• Vagina: The muscular tube leading from the uterus to the external genitalia.
• Digestive System:
• Rectum: Located posteriorly, similar to males.
• Part of the Colon: The sigmoid colon, which is located in the pelvic cavity.
• Vascular Structures:
• Pelvic Blood Vessels: Similar to males, the internal iliac arteries and veins supply the pelvis.
• Nerves: Sacral and coccygeal nerves provide innervation to the pelvic organs.

Pelvic Inlet & Outlet
The pelvic inlet is the superior opening of the true pelvis
Boundaries:
• Anteriorly: Pubic symphysis
• Laterally: Iliac bones
• Posteriorly: Sacrum
Function:
• Marks the boundary between the abdominal cavity (above) and the pelvic cavity (below)
The pelvic outlet is the inferior opening of the true pelvis.
Boundaries:
• Anteriorly: Pubic arch
• Laterally: Ischial tuberosities
• Posteriorly: Coccyx
Function:
• Provides the passage for the infant during childbirth (in females).
• Allows the passage of waste products from the rectum and urethra.

Pelvic Floor
The pelvic floor is a fibromuscular structure that forms the base of the
pelvis.
Function:
• Supports pelvic organs (bladder, uterus, rectum, etc.)
• Separates the pelvic cavity from the perineum (below)
• Helps in controlling urinary and fecal functions.
Components:
• Muscles:
• Levator ani
• Coccygeus
• Fascia:
• Connective tissue that supports the muscles.

Perineum
 The perineum is a diamond-shaped region located inferior to the pelvic floor, between the thighs
 The area of the body between the anus and the vulva in females, and between the anus and the scrotum
in males.
Boundaries:
• Anteriorly: Pubic symphysis
• Laterally: Ischial tuberosities
• Posteriorly: Coccyx
Components:
• External Openings: Anus, external urethral opening (penis/vagina)
• External Genitalia: Penis, scrotum (males); vulva, clitoris (females)
Divisions:
• Urogenital Triangle: Anterior, containing genitalia and urethra
• Anal Triangle: Posterior, containing the anus and anal canal
Muscles: Levator ani, external anal sphincter, urogenital diaphragm
Functions: Supports pelvic organs, aids in urinary, sexual, and defecatory functions.

• 3d: https://anatomy.app/article/pelvic-floor-and-perineum-female
• What is the True Pelvis? - Pelvic Inlet & Outlet Anatomy
https://www.youtube.com/watch?v=NB0-8WCo9X4
• 3D Tour of the Perineum
https://www.youtube.com/watch?v=lQzi1gKNgVU

Pelvis Bones
• Pelvic Bones:
• Consists of the right and left pelvic (hip) bones, sacrum, and coccyx.
• Articulations:
• Sacrum: Articulates superiorly with the 5th lumbar vertebra (LV) at the
lumbosacral joint.
• Pelvic Bones: Articulate posteriorly with the sacrum at the sacro-iliac joints.
• Pelvic Bones: Articulate anteriorly with each other at the pubic symphysis.

Pelvic Bone
Shape: Irregular in shape
Divisions: Separated by an oblique line:
• Above the line: Forms the lateral wall of the false pelvis (part of the abdominal cavity).
• Below the line: Forms the lateral wall of the true pelvis (contains the pelvic cavity).
Pelvic Inlet and Linea Terminalis
• Pelvic Inlet: Marks the transition from false pelvis to true pelvis.
• Linea Terminalis: Lower two-thirds of the oblique line contributing to the pelvic
inlet margin.
Acetabulum and Hip Joint
• Acetabulum: Large socket on the lateral surface of the pelvic bone.
• Combines with the femur head to form the hip joint.

Pelvic Bone
Obturator Foramen
• Location: Below the acetabulum.
• Structure: Mostly closed by the obturator membrane, leaving a small obturator canal open.
• Provides communication between the pelvic cavity and lower limb.
Posterior Margin Features
• Ischial Spine: Separates two notches:
• Greater Sciatic Notch (above).
• Lesser Sciatic Notch (below).
• Ischial Tuberosity: Large structure at the inferior end of the posterior margin.
Anterior Margin Features
• Marked by three key points:
• Anterior Superior Iliac Spine (ASIS).
• Anterior Inferior Iliac Spine (AIIS).
• Pubic Tubercle.

Components of the Pelvic Bone
The Pelvic Bone is Made Up of Three Parts:
• Ilium: The largest, uppermost part.
• Pubis: The anterior (front) part.
• Ischium: The lower, posterior (back) part.
Development: At birth, the ilium, pubis, and ischium are connected by
cartilage at the acetabulum.
• They fuse into a single bone between 16-18 years of age.

Ilium
The ilium (Latin: os ilium) is also known as the iliac bone. It is a paired bone
forming the uppermost and most significant part of the hip bone and the
skeleton of the pelvis.
Parts of ilium
• Each iliac bone is composed of two parts, and they are as follows: Body,
Wing
The body of the ilium is the central portion located above the acetabulum.
Part of the body also contributes to forming one-third of the acetabulum.
• The wing of the ilium is the large expanded superior portion of the ilium. The
wings of the ilium represent the lateral borders of the greater pelvis.

Wing of ilium
The wing of ilium(ala)is the largest upper part of the bone. It contains several important landmarks:
• The arcuate line is a bony ridge on the internal surface of the ilium. It separates the body and the
wing and forms the boundary between the greater and lesser pelvis.
• The iliac crest is the superior border of the wing. The iliac crest presents four bony projections
• The anterior superior iliac spine(ASIS) is a bony prominence that marks the anterior limit of the iliac
crest. It also serves as the origin site for the sartorius muscle.
• The anterior inferior iliac spine(AIIS) is located below the anterior superior iliac spine. It serves as
an origin site for the rectus femoris muscle.
• The posterior superior iliac spine(PSIS) marks the posterior limit of the iliac crest. It is an
attachment site for the posterior sacroiliac ligament and the lumbar multifidus muscles.
• The posterior inferior iliac spine(PIIS) is situated below the posterior superior iliac spine. Below this
spine is located a deep notch called the greater sciatic notch.

Wing of ilium
• The iliac fossa is a large and smooth concavity located on the internal
surface of the wing. It serves as the origin site for the iliacus muscle.
The sacropelvic surface corresponds to the posterior aspect of the inner
surface. It faces the sacrum. This surface consists of two parts:
The auricular surface is an ear-shaped(L), articulates with the sacrum-
sacroiliac joint.
The iliac tuberosity is a roughened and elevated area behind and above
the auricular surface. An attachment site for the posterior sacroiliac
ligaments and an origin site for the lumbar multifidus muscles.

Wing of ilium
The gluteal surface of the ilium is the external surface of the wing. This
surface presents with three ridges:
The anterior gluteal line is a flat ridge situated almost in the middle of the wing
on its external surface. The anterior gluteal line is the longest of all three lines.
The posterior gluteal line is also a bony ridge on the outer surface of the wing. It
is located posterior to the anterior gluteal line
The inferior gluteal line is a bony ridge located above the acetabulum and
inferior to the anterior gluteal line.

Pubic bone
• The pubic bone (Latin: os pubis) is a paired bone that forms the anterior
part of the hip bone.
• It also participates in the formation of the anterior and inferior boundary
of the obturator foramen.
• The left and right pubic bones join at the pubic symphysis.
• The pubic bone is the smallest hip bone, and it is continuous with
the ischium posteriorly and ilium superiorly.
• Each pubic bone has three parts - inferior and superior rami and the body.
Each body is located in the middle of both rami.

Pubic bone
Body of pubis
The body of pubis is the smallest part of the pubic bone. It contains three
surfaces - anterior or external, posterior or internal and medial. The medial
surface is also known as the symphysial surface.
It has a rounded pubic crest on its superior surface that ends laterally as the
prominent pubic tubercle.
Inferior ramus of pubis
The inferior ramus extends posteroinferiorly from the body part, and it merges
with the ramus of the ischium.
The inferior ramus has two surfaces - anterolateral and posteromedial - and two
borders named the medial and anterior borders.

Superior ramus of pubis
The superior ramus of the pubis extends superiorly and backward from the body
part. It features several landmarks:
The pubic tubercle is a bony prominence located on the upper aspect of the
superior ramus.
The sharp superior margin is termed the pecten pubis or the pectineal line. It
forms part of the linea terminalis and reaches the pubic tubercle as the
continuation of the arcuate line and serves as the origin site for
the pectineus muscle.
The obturator groove is a deep sulcus located on inferior surface of the superior
ramus above the acetabulum. The obturator vessels and nerves pass through the
groove. It forms the upper margin of the obturator canal .

Ischium
• The ischium (Latin: os ischii) is a paired bone of the pelvis.
• It forms the lower and posterior aspects of the hip bone and the posterior and inferior boundary
of the obturator foramen.
• The ischium is continuous with the pubic bone anteriorly and the ilium superiorly.
• This bone is composed of two main parts - the body and the ramus of the ischium.
Body of ischium
• The body of ischium is a broad and rough upper part of the bone that forms the posterior one-
third of the acetabulum.
• The body of the ischium has three surfaces - medial or pelvic, lateral or femoral and posterior
surface.

Ramus of ischium
The ramus of ischium extends downward from the body, turns forward and fuses with the
inferior ramus of the pubis.
Landmarks of the ramus:
• The ischial tuberosity is a bony process at the lower end of the lesser sciatic notch.
• The ischial spine is a bony prominence found on the ramus of the ischium between the
greater and lesser sciatic notches.
• The lesser sciatic notch is located below the ischial spine between it and the ischial
tuberosity.
• The greater sciatic notch is a larger notch located above the ischial spine between it and
the posterior inferior iliac spine.

Sacrum
• The sacrum (Latin: os sacrum) is a triangular-shaped bone located at the base of
the spine.
• As this bone is triangular-shaped, it presents a downward-directed apex and an upward-
directed base.
• It is formed by five sacral vertebrae (S1 - S5) that fuse with each other between ages 18
and 30.
• The sacrum articulates with four bones - the last (fifth) lumbar vertebra above,
the coccyx below, and the ilium on each its lateral side.
• The sacrum has four surfaces - pelvic, dorsal and two lateral surfaces.

Apex and base of sacrum
• The apex is connected to the coccyx. The joint between both bones is known as
the sacrococcygeal symphysis.
• The base is the broad upper part featuring the promontory and two superior articular processes.
• The promontory is a prominent upper anterior margin of the body of the first sacral vertebra. Its
anterior aspect projects far into the pelvic cavity.
• The superior articular processes are two large projections on the posterior aspect of the base.
They articulate with the inferior articular processes of the fifth lumbar vertebra, forming
the lumbosacral joint.
• The superior surface of the sacrum is formed by the upper part of the body of the first sacral
vertebra (S1), with each side featuring a broadened, wing-like transverse process called the ala.

Pelvic surface of sacrum
The pelvic surface of the sacrum is the anterior surface that faces the
pelvic cavity. It is concave and presents the following landmarks:
• The transverse lines are four lines corresponding to the fusion sites
between the bodies of all five sacral vertebrae.
• The anterior sacral foramina are four pairs of anterior openings in the
sacrum. Through the openings pass nerves and blood vessels.

Dorsal surface of sacrum
The dorsal surface is the posterior convex surface of the sacrum. It contains various anatomical landmarks:
• The median sacral crest is a ridge located in the midline of the surface. It is formed by the remnants of the
spinous processes of the sacral vertebrae (S1-S4).
• The intermediate sacral crests are two ridges located on either side of the median crest. They are formed by
the fusion of articular processes of the sacral vertebrae.
• The lateral sacral crests are paired ridges laterally from the posterior sacral foramina on either side of the
surface. They are remnants of transverse processes of the sacral vertebrae.
• The posterior sacral foramina are four pairs of posterior openings in the sacrum. Through these openings
pass nerves and blood vessels.
• The sacral canal is the inferior end of the vertebral canal running through most of the sacrum. The canal
does not contain the spinal cord as the filum terminale starts at the L2 level.
• The sacral hiatus is the inferior opening of the sacral canal. It is located in the posterior wall of the sacral
canal, usually at the level of the S3 - S4
• The sacral cornu (sacral horns) are two processes extending downward on each side of the sacral hiatus.
They are remnants of the inferior articular processes of the fifth sacral vertebra.

Lateral surfaces of sacrum
The lateral surfaces are derived from the fusion of rudimentary ribs and
transverse processes of the sacral vertebrae. They present the following
landmarks:
• The auricular surface is an ear-shaped(L) articular surface situated on each lateral
part of the sacrum.
• This surface articulates with the same-named surface of the ilium, and both
bones form the sacroiliac joint.
• The sacral tuberosity is a rough and elevated area on each lateral surface of the
sacrum posterior to the auricular surface.
• It serves as an attachment site for the posterior sacroiliac ligaments.

Coccyx
• The coccyx (Latin: os coccygis), also known as the tailbone, is the final part of
the vertebral column consisting of three to five rudimentary vertebrae that lack the
vertebral arches, therefore no bony vertebral canal is present in the coccyx.
• It is located below the sacrum, and both bones are connected by the sacrococcygeal
symphysis.
• The coccyx is a triangular-shaped bone with its base facing the sacrum while its apex is
facing downward.
• Each side of the base contains a coccygeal cornu (horn) - a rudimentary superior
articular process projecting upward from the base.
• The base of the coccyx presents with one articular facet. Also, the first coccygeal
vertebra has two transverse processes.

Lumbosacral Joints
Between vertebra LV (lumbar vertebra 5) and the sacrum.
Components:
• Zygapophysial Joints(2):
• Between adjacent inferior and superior articular processes of the vertebrae.
• Intervertebral Disc:
• Joins the bodies of vertebra LV and SI (sacral vertebra 1).
Key Characteristics:
• Sacrum Angles Posteriorly:
• Resulting in a thicker anterior disc than posterior.
Reinforcement:
• Iliolumbar Ligament: From vertebra LV to ilium.
• Lumbosacral Ligament: From vertebra LV to sacrum.

Sacro-Iliac Joints
• Function: Transmit forces from the lower limbs to the vertebral column.
Articulation:
• Type: Synovial joints.
• Articular Facets: L-shaped facets on the lateral surfaces of the sacrum and
similar facets on the iliac parts of the pelvic bones.
Joint Characteristics:
• Irregular Contours: Joint surfaces interlock to resist movement.
• Aging: Joints may become fibrous with age and may ossify completely.

Ligaments Stabilizing Sacro-Iliac Joints
• Anterior Sacro-Iliac Ligament:
• Thickening of the fibrous membrane.
• Runs anteriorly and inferiorly to the joint.
• Interosseous Sacro-Iliac Ligament:
• Largest and strongest.
• Positioned posterior-superior to the joint.
• Fills the gap between the ilium and sacrum.
• Posterior Sacro-Iliac Ligament:
• Covers the interosseous sacro-iliac ligament.

Pubic Symphysis Joint
• Location: Lies anteriorly between the adjacent surfaces of the pubic bones.
Joint Structure:
• Hyaline Cartilage: Covers each joint surface.
• Fibrocartilage: Links the surfaces across the midline.
Ligaments:
• Superior Pubic Ligament:
• Located above the joint.
• Inferior Pubic Ligament:
• Located below the joint.
• Support:Surrounded by interwoven collagen fibers providing additional stability.

Orientation of the Pelvis
Anatomical Position:
In the anatomical position, the pelvis is oriented so that:
• The front edge of the top of the pubic symphysis the anterior superior iliac spines
lie in the same vertical plane.
Pelvic Inlet:
• The pelvic inlet, marking the entrance to the pelvic cavity, is tilted
anteriorly.
Pelvic Bones:
• The pubic bones and pubic arch are positioned in a nearly horizontal
plane facing the ground.

Differences Between Male and Female Pelvis
The pelvises of women and men differ in a number of ways, many of which have to do with the passing of a baby
through a woman’s pelvic cavity during childbirth.
1. Pelvic Inlet Shape:
• Women: Circular shape
• Men: Heart-shaped shape
• Reason: The more circular shape in women is partly due to a less distinct promontory and broader alae.
2. Pubic Arch Angle:
• Women: Angle between the arms of the pubic arch is larger (80°–85°).
• Men: Angle is smaller (50°–60°).
3. Ischial Spines:
• Women: Less medially projecting ischial spines.
• Men: More medially projecting ischial spines.

Overview of the Lower Limb
The lower limb supports body weight, balance, and locomotion.
Regions of the Lower Limb
• Pelvic Region: Pelvis, hip joint.
• Thigh: Femur, quadriceps, hamstrings.
• Knee: Patella, knee joint.
• Leg: Tibia, fibula.
• Ankle: Talus, calcaneus.
• Foot: Tarsals, metatarsals, phalanges.
• upports body weight, balance, and locomotion.

Lower Limb Connection to the Axial Skeleton
The lower limb is anchored to the central skeleton (axial skeleton) and separated
from nearby body regions by a series of bony landmarks and ligaments.
Connection to the Axial Skeleton:
• Sacroiliac Joint: A strong joint between the sacrum and iliac bone that transfers
body weight from the spine to the lower limb.
• Strong Ligaments: The sacroiliac and sacrotuberous ligaments provide additional
stability.

Boundaries Separating the Lower Limb from Other
Body Regions
The lower limb is separated from the abdomen, back, and perineum by an
imaginary continuous line connecting these key structures:
• Anterior (Front) – Separates from the abdomen
• Pubic tubercle to Anterior Superior Iliac Spine (ASIS)
• Follows the inguinal ligament and the iliac crest (hip bone).
• Posterior (Back) – Separates from the back muscles
• Posterior Superior Iliac Spine (PSIS)
• Extends along the dorsal sacrum to the coccyx.
• Inferior (Bottom) – Separates from the perineum (area between the thighs)
• Sacrotuberous ligament, Ischial tuberosity (sit bone)
• Ischiopubic ramus and Pubic symphysis.

Connections Between Lower Limb and Axial
Skeleton
1. Sacroiliac Joint (Structural Anchoring)
• Connects the sacrum (axial skeleton) to the iliac bone of the pelvis.
• Transfers body weight from the spine to the lower limbs.
• Provides stability, not movement.
• Reinforced by strong sacroiliac ligaments.
2. Hip Joint (Functional Movement Connection)
• Ball-and-socket synovial joint between the femur head and acetabulum.
• Allows movement (flexion, extension, rotation).

Regions of the Lower Limb
Gluteal Region:
• Located posterolaterally (back and side) of the body.
• Bound by the iliac crest and the gluteal fold (lower limit of the buttocks).
Thigh:
• Anteriorly: Between the inguinal ligament and knee joint.
• Posteriorly: Between the gluteal fold and the knee.
• Hip joint: Located just below the middle third of the inguinal ligament.
Leg:
• Area between the knee and ankle joint.
Foot:
• Located distally (farther from the body) to the ankle joint.

Important Transitional Areas in the Lower Limb
Femoral Triangle:
• Shape: Pyramid-shaped depression in the proximal thigh.
• Boundaries: Formed by thigh muscles and the inguinal ligament (base).
• Function: Major blood vessels and the femoral nerve pass from the abdomen
into the thigh through this region.
Popliteal Fossa:
• Shape: Diamond-shaped region located posterior to the knee joint.
• Boundaries: Formed by muscles of the thigh and leg.
• Function: Major vessels and nerves pass between the thigh and leg.
Posteromedial Side of the Ankle (Tarsal Tunnel):
• Canals: Structures (nerves, vessels, and flexor tendons) pass through a series
of canals.
• Formed by: Adjacent bones and a flexor retinaculum that holds tendons in
place.

Functions of the Lower Limb
Support the Body Weight:
• Primary Function: The lower limb supports the body's weight with minimal energy.
• Body Alignment:
• The center of gravity is anterior to the SII vertebra (in the pelvis).
• The vertical line is slightly posterior to the hip joints, anterior to the knee and ankle joints, and directly over
the feet.
• Joint Mechanism:
• Hip and knee ligaments, along with joint shapes, help lock these joints in position when standing.
• This locking reduces the muscular energy needed to maintain a standing posture.
Locomotion:
• The lower limbs help in moving the body through space.
• Involves the integration of movements at all joints to position the foot on the ground and propel
the body over it.

Movements at the Hip, Knee, and Ankle Joints
Hip Joint Movements:
• Flexion: Thigh moves forward.
• Extension: Thigh moves backward.
• Abduction: Thigh moves away from the midline.
• Adduction: Thigh moves toward the midline.
• Medial Rotation: Thigh rotates inward.
• Lateral Rotation: Thigh rotates outward.
• Circumduction: Circular movement of the hip joint.
• Visual: Diagram illustrating these movements at the hip joint.

Knee Joint Movements:
• Flexion: Knee bends (thigh and
calf move closer).
• Extension: Knee straightens
(thigh and calf move apart).
Ankle Joint Movements:
• Dorsiflexion: Foot moves
upward toward the leg.
• Plantarflexion: Foot moves
downward away from the leg.

Lower Limb Anatomy and Energy Efficiency in Walking
Lower Limb Anatomy in Walking:
• Contributes to minimizing fluctuations in the center of gravity.
• Reduces energy expenditure for smooth, efficient locomotion.
Key Anatomical Features Involved:
• Pelvic Tilt (Coronal Plane): Helps stabilize the body's vertical alignment.
• Pelvic Rotation (Transverse Plane): Provides smooth transition during steps.
• Knee Movement Toward Midline: Helps maintain balance and alignment.
• Knee Flexion: Reduces vertical oscillations and smooths walking motion.
• Complex Interactions: Between hip, knee, and ankle joints for coordinated movement.
Result of Efficient Gait:
• Body’s center of gravity fluctuates only 5 cm vertically and laterally during walking.

Pelvic Tilt (Coronal Plane)
• Pelvic tilt refers to the forward or backward rotation of the pelvis in the coronal plane (side view).
• A slight anterior pelvic tilt (forward rotation) helps maintain the natural curve of the spine, and a posterior tilt
(backward rotation) helps stabilize the body. This movement is important for aligning the trunk over the lower
limbs and ensures proper posture during walking.
Pelvic Rotation (Transverse Plane)
• Pelvic rotation involves the rotation of the pelvis around its vertical axis, which occurs in the transverse plane
(from a top-down view).
• The pelvis rotates slightly to help the legs swing in a forward motion while walking, especially to avoid any
excessive lateral (side-to-side) movement of the body.
Knee Movement Toward Midline
• The knee moves slightly towards the body's midline as part of the walking cycle.
• This inward movement, called knee adduction, ensures that the legs stay aligned with the body's center of
gravity and helps with balance.
Knee Flexion
• Knee flexion refers to the bending of the knee joint, which reduces the angle between the thigh and the lower
leg.
• Knee flexion is crucial during the stance phase (when the foot is in contact with the ground), especially when
absorbing the impact forces of walking or running.

Complex Interactions Between Hip, Knee, and
Ankle Joints
• The hip, knee, and ankle joints work together to control and coordinate
movement during walking. Each joint plays a role in different parts of the stride
cycle:
• Hip: Moves in flexion and extension, providing forward and backward leg movement.
• Knee: Alternates between flexion and extension, adjusting the length of the stride and
providing stability.
• Ankle: Performs dorsiflexion (lifting the foot) and plantarflexion (pointing the toes
downward) to control foot placement and push off.
• The interactions between these joints ensure that the movement is smooth,
controlled, and coordinated during each step. They must work in sync to
maintain a natural and balanced gait.
• These joint interactions prevent any jerky movements, making walking efficient
and reducing the strain on any single joint. It ensures the legs move in a
controlled, rhythmic manner, helping to maintain a consistent pace and energy-
efficient movement.

Bones and Joints of the Gluteal Region and Thigh
Bones Involved:
• Pelvic Bone & Femur: Primary bones of the gluteal region and thigh.
• Femur: Articulates distally with the Tibia (weight-bearing) and Patella (knee cap).
• Joints:
• Hip Joint: Ball-and-socket joint between pelvic bone and femur.
• Knee Joint:
• Femur-Tibia Joint: Main weight-bearing articulation.
• Patella-Femur Joint: Shares the same articular cavity.
• Patella:
• Largest sesamoid bone, embedded in the Quadriceps Femoris Tendon.
Knee Joint Movements:
• Primary: Flexion and Extension.
• Additional: Femoral rotation on tibia, aiding in knee "locking" during full extension, especially
when standing.

Bones and Joints of the Leg
• Bones Involved:
• Tibia: Medial, larger, and weight-bearing bone.
• Fibula: Lateral bone, does not participate in the knee joint, forms part of the ankle
joint.
• Joints:
• Superior Tibiofibular Joint: Small synovial joint between the fibula and tibia head.
• Inferior Tibiofibular Joint: Fibrous joint linking the tibia and fibula at the distal end
with minimal movement.(syndesmosis)
• Ankle Joint:
• Formed by the distal ends of the tibia and fibula, and the Talus (tarsal bone).
• Most stable when the ankle is dorsiflexed (foot flexed upward).

Bones of the Foot
• The foot consists of three main groups of bones:
• Tarsal bones
• Metatarsals
• Phalanges
• Tarsal Bones:
• There are seven tarsal bones, organized in two rows.
• An intermediate bone lies between the two rows on the medial side.
• Foot Movement:
• Inversion: Turning the sole of the foot inward.
• Eversion: Turning the sole of the foot outward.
• These movements occur at the joints between the tarsal bones.

Articulation and Movement of Foot Bones
• Tarsometatarsal Joints:
• The tarsal bones articulate with the metatarsals at the tarsometatarsal joints.
• These joints allow only limited sliding movements.
• Deep Transverse Metatarsal Ligaments:
• Restrict independent movement of the metatarsals by linking the distal heads of the metatarsal bones at the
metatarsophalangeal joints.
• Metatarsal and Phalangeal Structure:
• There is a metatarsal for each of the five digits.
• Each digit has three phalanges, except for the great toe (digit I), which has two.
• Metatarsophalangeal Joints:
• Allow flexion, extension, abduction, and adduction of the digits.
• The range of movement is more restricted compared to the hand.
• Interphalangeal Joints:
• These are hinge joints that allow flexion and extension.

Foot Arches
• Foot Structure:
• The bones of the foot do not lie flat on the ground; they form longitudinal
and transverse arches
• Longitudinal Arch:
• The highest point is on the medial side of the foot.
• Function of Foot Arches:
• The arches are flexible and provide support.
• They are maintained by muscles and ligaments.
• The arches absorb and transmit forces during walking and standing.

Regional Anatomy: Bony Pelvis
• Pelvic Bones:
• Each pelvic bone is formed by three bones: ilium, ischium, and pubis.
• These bones fuse during childhood, with the ilium being superior and the pubis and ischium being
anteroinferior and posteroinferior, respectively.
• Articulations:
• The ilium articulates with the sacrum.
• The pelvic bone is anchored to the vertebral column (sacrum and coccyx) by the sacrotuberous
and sacrospinous ligaments, attaching to the tuberosity and spine of the ischium.
• Muscle Attachments:
• The outer surface of the ilium, along with the sacrum, coccyx, and sacrotuberous ligament, are
associated with the gluteal region.
• The ischial tuberosity provides attachment for muscles of the posterior thigh.
• The ischiopubic ramus and pubis are associated with muscles of the medial thigh.
• Femoral Head Articulation:
• The head of the femur articulates with the acetabulum on the lateral surface of the pelvic bone.

Ilium: Structure and Features
• Upper Fan-Shaped Part:
• The upper part of the ilium is associated with the abdomen on its inner side
and the lower limb on its outer side.
• The top of the ilium is the iliac crest, ending:
• Anteriorly at the anterior superior iliac spine.
• Posteriorly at the posterior superior iliac spine.
• The tuberculum of the iliac crest is a prominent lateral expansion just
posterior to the anterior superior iliac spine.
• Anterior Inferior Iliac Spine:
• Located on the anterior margin of the ilium, below which is the iliopubic
eminence, a raised area where the ilium fuses with the pubis.

Gluteal Surface of the Ilium
• The gluteal surface of the ilium faces posterolaterally and lies below
the iliac crest.
• Three curved lines (inferior, anterior, and posterior gluteal lines)
divide the surface into four regions.

Muscle Attachments
• Inferior Gluteal Line:
• Originates just superior to the anterior inferior iliac spine and curves inferiorly to near the
posterior margin of the acetabulum.
• The rectus femoris muscle attaches to the anterior inferior iliac spine and to the roughened
bone between the superior acetabulum and inferior gluteal line.
• Anterior Gluteal Line:
• Originates from the lateral margin of the iliac crest between the anterior superior iliac spine
and tuberculum of the iliac crest.
• The gluteus minimus muscle originates from between the inferior and anterior gluteal lines.
• Posterior Gluteal Line:
• Descends vertically from the iliac crest to near the posterior inferior iliac spine.
• The gluteus medius muscle attaches between the anterior and posterior gluteal lines, while
the gluteus maximus muscle attaches posteriorly to the posterior gluteal line.

Ischial Tuberosity: Overview
• Located posteroinferior to the acetabulum.
• Primarily associated with the hamstring muscles of the posterior
thigh
• Divided into upper and lower areas by a transverse line.

Upper Area of Ischial Tuberosity
• Oriented vertically.
• Further subdivided by an oblique line (descending from medial to
lateral).
• Medial Part:
• Attachment for the semitendinosus muscle and the long head of the biceps femoris
muscle.
• Lateral Part:
• Attachment for the semimembranosus muscle.

Lower Area of Ischial Tuberosity
• Oriented horizontally, divided into medial and lateral regions by a
ridge of bone.
• Lateral Region:
• Attachment for part of the adductor magnus muscle.
• Medial Region:
• Faces inferiorly and is covered by connective tissue and a bursa.
• Supports body weight when sitting.
• Sacrotuberous Ligament:
• Attached to a sharp ridge on the medial margin of the ischial tuberosity.

Ischiopubic Ramus and Pubic Bone: Muscle Attachments
• The external surfaces of the ischiopubic ramus anterior to the ischial
tuberosity and the body of the pubis provide attachment for muscles of the
medial compartment of the thigh
• Muscles Involved:
• Adductor longus
• Adductor brevis
• Adductor magnus
• Pectineus
• Gracilis

Acetabulum
• Location:
• The acetabulum is a large cup-shaped structure on the lateral surface of the
pelvic bone.
• It is formed where the ilium, pubis, and ischium fuse
Function:
• Articulates with the head of the femur to form the hip joint.

Structure of the Acetabulum
• The margin of the acetabulum is marked by the acetabular notch
(inferiorly).
• Wall Composition:
• Nonarticular Part:
• Rough surface forming the acetabular fossa, a shallow circular depression in the central
and inferior parts of the acetabular floor.
• Continuity: The acetabular notch is continuous with the acetabular fossa.
• Articular Part:
• The smooth, crescent-shaped lunate surface.
• Broadest superiorly (where the body's weight is transmitted to the femur).
• Deficient inferiorly at the acetabular notch.

Function and Attachments
• Articular Surface:
• The lunate surface surrounds the anterior, superior, and posterior margins of
the acetabular fossa.
• Acetabular Fossa:
• Provides attachment for the ligament of the head of the femur.
• Acetabular Notch:
• Allows blood vessels and nerves to pass through.

Proximal Femur: Overview
• Bone Description:
• The femur is the longest bone in the body, located in the thigh.
• Proximal End:
• Head: Spherical, articulates with the acetabulum of the pelvic bone.
• Contains a nonarticular pit (fovea) on the medial surface for the attachment of the
ligament of the head.
• Neck: Cylindrical bone structure that connects the head to the femoral shaft.
• Projects superomedially at an angle of approximately 125°.
• Projects slightly forward, increasing the range of movement of the hip joint.
• Greater and Lesser Trochanters:
• Located on the upper part of the femoral shaft.
• Serve as attachment sites for muscles that move the hip joint.

Greater Trochanter: Structure & Attachments
• Location:
• Extends superiorly from the femoral shaft, just lateral to where the shaft joins the
neck of the femur.
• Trochanteric Fossa:
• Medial surface has a deep groove forming the trochanteric fossa.
• Obturator externus muscle attaches to an oval depression on the lateral wall of the
fossa.
• Attachment Sites:
• Gluteus minimus: Anterolateral surface.
• Gluteus medius: Posterior part of the lateral surface.
• Obturator internus and gemelli muscles: Superior medial aspect, just above the
trochanteric fossa.
• Piriformis muscle: Immediately above and behind the obturator internus impression.

Lesser Trochanter: Structure & Attachments
• Location:
• Smaller, blunt, conical shape.
• Projects posteromedially from the femoral shaft just inferior to the neck.
• Attachment Site:
• Site of attachment for the combined tendons of psoas major and iliacus
muscles.
• Intertrochanteric Structures:
• Intertrochanteric line and intertrochanteric crest: Separate the femoral shaft
from the neck, extending between the two trochanters.

Intertrochanteric Line & Crest: Structure and Function
Intertrochanteric Line:
• Location:
• Anterior surface of the upper femoral shaft.
• Descends medially from a tubercle at the base of the greater trochanter to
just anterior to the lesser trochanter.
• Continuity:
• It merges with the pectineal line (spiral line), which curves medially under the
lesser trochanter and around the femoral shaft to the medial margin of the
linea aspera on the posterior femur.

Intertrochanteric Crest
• Location:
• Posterior surface of the femur.
• Descends medially from the posterior margin of the greater trochanter to the
base of the lesser trochanter.
• Features:
• Broad smooth ridge of bone with a prominent quadrate tubercle on the
upper half.
• The quadrate tubercle serves as the attachment point for the quadratus
femoris muscle.

Overview of the Shaft of the Femur
• Angle of Descent:
• The shaft of the femur descends from lateral to medial in the coronal plane.
• The shaft has a 7° angle from the vertical axis, meaning the distal end is closer
to the midline than the upper end.
• Shape:
• The middle third of the shaft is triangular in shape.
• Smooth lateral and medial margins define the anterior, lateral
(posterolateral), and medial (posteromedial) surfaces.

Linea Aspera
• Linea Aspera:
• The broad posterior margin of the femur forms the linea aspera, a prominent
raised crest.
• It serves as a major muscle attachment site on the posterior femur.
• Proximal Divergence:
• The medial and lateral margins of the linea aspera diverge in the proximal
third of the femur, continuing superiorly as:
• Pectineal Line (medially)
• Gluteal Tuberosity (laterally)

Pectineal Line, Gluteal Tuberosity, and Posterior
Surface
• Pectineal Line:
• Curves anteriorly under the lesser trochanter.
• Joins the intertrochanteric line.
• Gluteal Tuberosity:
• A broad, linear roughening that curves laterally to the base of the greater
trochanter.
• Serves as the attachment site for the gluteus maximus muscle.
• Posterior Surface:
• The triangular area enclosed by the pectineal line, gluteal tuberosity, and
intertrochanteric crest forms the posterior surface of the proximal femur.

Hip Joint: Structure and Function
• Type of Joint:
• Synovial articulation between:
• The head of the femur.
• The acetabulum of the pelvic bone.
• Multiaxial ball and socket joint designed for:
• Stability and weight-bearing.
• Limited mobility in exchange for stability.
• Movements:
• Flexion, extension, abduction, adduction.
• Medial and lateral rotation, circumduction.
• Muscle Action:
• Rotation of the femur involves muscles that move the greater trochanter relative to the acetabulum.
• The long neck of the femur and its angulation affect movement.

Articular Surfaces and Ligaments of the Hip Joint
• Articular Surfaces:
• Head of the Femur: Spherical, covered with hyaline cartilage (except the fovea).
• Lunate Surface of the Acetabulum: Covered by hyaline cartilage, broadest superiorly.
• Acetabulum:
• Almost entirely encloses the femoral head, contributing significantly to joint stability.
• Acetabular Fossa: Contains loose connective tissue.
• Acetabular Labrum:
• A fibrocartilaginous collar that raises the rim of the acetabulum.
• Transverse Acetabular Ligament:
• Bridges across the acetabular notch, converting it into a foramen.
• Ligament of the Head of the Femur:
• Flat band of connective tissue, attaches:
• Fovea of the femoral head.
• Acetabular fossa, transverse acetabular ligament, and acetabular notch.
• Contains a small branch of the obturator artery, contributing to the blood supply of the femoral head.

Synovial and Fibrous Membranes of the Hip Joint
• Synovial Membrane:
• Attaches to the margins of the articular surfaces of the femur and acetabulum.
• Forms a tubular covering around the ligament of the head of the femur.
• Covers the neck of the femur before reflecting onto the fibrous membrane.
• Fibrous Membrane:
• Strong and thick, enclosing the entire hip joint.
• Medial Attachments:
• Margin of the acetabulum.
• Transverse acetabular ligament.
• Adjacent margin of the obturator foramen.
• Lateral Attachments:
• Intertrochanteric line on the anterior femur.
• Neck of the femur just proximal to the intertrochanteric crest (posterior surface).

Ligaments of the Hip Joint
• The hip joint is stabilized by three ligaments:
• Iliofemoral ligament (anterior)
• Pubofemoral ligament (anteroinferior)
• Ischiofemoral ligament (posterior)
• Ligament fibers are spirally oriented around the joint, becoming
stretched during extension, enhancing joint stability.

Iliofemoral Ligament
• Location: Anterior to the hip joint. Shape: Triangular with a Y-shaped appearance.
• Attachments:
• Apex: Ilium between the anterior inferior iliac spine and acetabular margin.
• Base: Intertrochanteric line of the femur.
• Function: Prevents hyperextension and provides anterior stability.
Pubofemoral Ligament
• Location: Anteroinferior to the hip joint. Shape: Triangular.
• Attachments:
• Base: Iliopubic eminence, adjacent bone, and obturator membrane.
• Laterally: Blends with the fibrous membrane and deep surface of the iliofemoral ligament.
• Function: Prevents excessive abduction and reinforces inferior stability.
Ischiofemoral Ligament
• Location: Posterior to the hip joint.
• Attachments:
• Medial: Ischium (posteroinferior to acetabulum).
• Lateral: Greater trochanter (deep to iliofemoral ligament).
• Function: Provides posterior reinforcement and prevents excessive internal rotation.

Vascular & Nerve Supply
• Main Arteries:
• Obturator artery.
• Medial & lateral circumflex femoral arteries.
• Superior & inferior gluteal arteries.
• First perforating branch of the deep artery of the thigh.
• Articular branches of these vessels form a vascular network around the
joint
• Innervation:
• Femoral nerve.
• Obturator nerve.
• Superior gluteal nerve.
• Nerve to quadratus femoris.

Obturator Canal
A vertically oriented passageway located at the anterosuperior edge of the obturator foramen.
Borders:
• Superior: Obturator groove on the inferior surface of the superior ramus of the pubic bone.
• Inferior: Upper margin of the obturator membrane.
• Muscles: Obturator internus and externus, attached to the obturator membrane and surrounding
bone.
Function:
• Connects the abdominopelvic region to the medial compartment of the thigh.
• Transmits:
• Obturator nerve
• Obturator vessels

Greater Sciatic Foramen
A major passageway on the posterolateral pelvic wall, connecting the pelvis to the gluteal
region of the lower limb.
Borders:
• Anterior: Greater sciatic notch
• Superior: Upper borders of the sacrospinous and sacrotuberous ligaments
• Medial: Lateral border of the sacrum
Contents:
• Piriformis Muscle: Divides the foramen into two parts:
• Above Piriformis: Superior gluteal nerve and vessels
• Below Piriformis:
• Sciatic nerve
• Inferior gluteal nerve and vessels
• Pudendal nerve and internal pudendal vessels
• Posterior cutaneous nerve of the thigh
• Nerve to obturator internus and gemellus superior
• Nerve to quadratus femoris and gemellus inferior

Lesser Sciatic Foramen
Located inferior to the greater sciatic foramen,
connecting the gluteal region with the perineum.
Borders:
• Superior: Lateral attachment of the pelvic floor
(levator ani and coccygeus muscles)
• Medial: Sacrospinous ligament
• Lateral: Pelvic wall
Contents:
• Obturator Internus Tendon: Passes through the
foramen from the lateral pelvic wall into the gluteal
region to insert on the femur
• Pudendal Nerve & Internal Pudendal Vessels:
• Exit the pelvis through the greater sciatic foramen
below the piriformis
• Enter the perineum through the lesser sciatic foramen,
passing around the ischial spine and sacrospinous
ligament

Gap Between the Inguinal Ligament and Pelvic Bone
• A large crescent-shaped gap located between the inguinal ligament (above) and the
anterosuperior margin of the pelvic bone (below).
• Major route of communication between the abdomen and anteromedial aspect of the thigh.
Contents Passing Through:
• Muscles:
• Psoas Major
• Iliacus
• Pectineus
These muscles pass through the gap to insert onto the femur.
• Vessels:
• Femoral Artery
• Femoral Vein
These major blood vessels and lymphatics of the lower limb also pass through this gap.
• Nerves:
• Femoral Nerve
Enters the femoral triangle of the thigh.

Thigh Anatomy Overview
• Location: The thigh is the region between the hip and knee joints.
Boundaries:
• Anteriorly: Separated from the abdominal wall by the inguinal ligament.
• Posteriorly: Separated from the gluteal region by the gluteal fold superficially and by the
gluteus maximus and quadratus femoris on deeper planes.
Key Routes:
• Posteriorly: The thigh is continuous with the gluteal region, with the sciatic nerve
passing between them.
• Anteriorly: Communicates with the abdominal cavity through the aperture between the
inguinal ligament and pelvic bone (passing iliopsoas and pectineus muscles; femoral
nerve, artery, and vein; lymphatic vessels).
• Medially: Structures pass through the obturator canal, including the obturator nerve
and associated vessels.

Compartments of the Thigh
The thigh is divided into three compartments by intermuscular septa and fascia
lata:
• Anterior Compartment:
• Contains muscles that mainly extend the leg at the knee joint.
• Innervation: Femoral nerve.
• Posterior Compartment:
• Contains muscles that mainly extend the thigh at the hip joint and flex the leg at the knee
joint.
• Innervation: Sciatic nerve.
• Medial Compartment:
• Contains muscles that mainly adduct the thigh at the hip joint.
• Innervation: Obturator nerve.

Bones of the Thigh
• Femur:
• The main skeletal support for the thigh.
• Most of the large muscles in the thigh insert into the proximal ends of the tibia
and fibula.
• These muscles are responsible for flexing and extending the leg at the knee
joint.
• Distal End of Femur:
• Provides origin for the gastrocnemius muscles.
• The gastrocnemius is primarily located in the posterior compartment of the leg
and is involved in plantarflexing the foot.

Shaft and Distal End of the Femur
• Femur Shaft:
• Shape: The shaft is bowed forward with an oblique course from the neck of the femur to the distal end.
• Function: The oblique orientation brings the knee closer to the body's midline and under its center of gravity.
• Middle Part of the Shaft:
• Cross-Section: Triangular in shape.
• Surfaces:
• Medial (posteromedial)
• Lateral (posterolateral)
• Anterior
• Borders: Rounded medial and lateral borders, broad roughened posterior border (linea aspera).
• Distal End of the Femur:
• The linea aspera widens to form an additional posterior surface.
• The posterior surface forms the floor of the popliteal fossa, with margins creating the medial and lateral
supracondylar lines.
• The medial supracondylar line ends at the adductor tubercle on the medial condyle.
• An elongate roughened area is present for the proximal attachment of the medial head of the gastrocnemius
muscle.

Distal End of the Femur
• Key Features:
• Characterized by two large condyles
• Articulate with the proximal head of the tibia
• Separated by the intercondylar fossa posteriorly
• Joined anteriorly where they articulate with the patella
Condyles and Articulation with Tibia
• Condyles:
• Rounded posteriorly
• Become flatter inferiorly as they articulate with the tibia
• Grooves:
• Shallow oblique groove separates tibial and patellar articulating surfaces
• V-shaped trench:
• Formed by the medial and lateral condyles for patella articulation
• Lateral surface: Larger and steeper than medial surface

Intercondylar Fossa and Cruciate Ligament
Attachment
Intercondylar Fossa: Contains two facets for
cruciate ligament attachment
• Cruciate Ligaments: Stabilize the knee joint
• Posterior Cruciate Ligament (PCL):
• Attachment: Lateral surface of the medial condyle
• Facet: Large oval facet covering most of the
inferior half of the wall
• Anterior Cruciate Ligament (ACL):
• Attachment: Medial surface of the lateral condyle
• Facet: Smaller posterosuperior oval facet

Epicondyles and Their Attachments
Epicondyles of the Femur:
• Bony elevations on the non-articular outer surfaces of the condyles
• Function: Attachment points for collateral ligaments of the knee joint
• Lateral Epicondyle:
• Facets Posterior to the Lateral Epicondyle:
• Upper Facet: Attachment of the lateral head of the gastrocnemius muscle
• Inferior Facet: Attachment of the popliteus muscle
• Popliteus Tendon: Lies in the groove separating the two facets
• Medial Epicondyle:
• Rounded eminence on the medial surface of the medial condyle
• Adductor Tubercle: Located just posterosuperior to the medial epicondyle

Patella (Knee Cap)
• The patella is the largest sesamoid bone in the body.
• Formed within the tendon of the quadriceps femoris muscle as it crosses anterior to
the knee joint.
• Shape and Structure:
• Triangular Shape:
• Apex: Pointed inferiorly, attaches to the patellar ligament, which connects the patella to the
tibia.
• Base: Broad and thick, attaches to the quadriceps tendon from above.
• Articulates with the femur, has medial and lateral facets.
• Smooth Raised Ridge: Separates the two facets.
• Lateral Facet: Larger, articulates with the larger surface on the lateral condyle of the femur.

Proximal End of Tibia
• The tibia is the medial and larger of the two bones in the leg.
• It is the only bone that articulates with the femur at the knee joint.
• Structure of the Proximal End:
• Expanded for Weight-Bearing:
• Consists of a medial condyle and a lateral condyle.
• Both condyles are flattened in the horizontal plane and overhang the shaft.
• The superior surfaces of the condyles are articular, separated by the intercondylar region.
• The intercondylar region contains attachment sites for cruciate ligaments and menisci.
• Tibial Plateau:
• The articular surfaces of the medial and lateral condyles, along with the intercondylar region, form
the tibial plateau.
• The tibial plateau articulates with and is anchored to the distal end of the femur.
• Tibial Tuberosity:
• Inferior to the condyles, on the proximal shaft, is the tibial tuberosity.
• There are also roughenings for muscle and ligament attachments.

Tibial Condyles Overview
Structure:
• Medial Condyle:
• Larger, better supported over the shaft of the tibia.
• Larger, oval superior surface articulates with the medial femoral condyle.
• Articular surface extends laterally to the medial intercondylar tubercle.
• Lateral Condyle:
• Smaller, circular superior surface for articulation with the lateral femoral condyle.
• Circular superior surface articulates with the lateral femoral condyle.
• Articular surface extends to the lateral intercondylar tubercle.
• Both condyles are concave centrally, flatter around the edges.
• In contact with interarticular discs (menisci) in the knee joint.
Nonarticular Surfaces of the Tibial Condyles
• Medial Condyle: Posterior surface: Distinct horizontal groove for attachment of semimembranosus muscle.
• Lateral Condyle: Undersurface: Circular facet for articulation with the proximal head of the fibula.

The Intercondylar Region
• Location: Between the articular surfaces of the medial and lateral condyles.
• Structure:
• Raised to form the intercondylar eminence.
• Sides elevated further into medial and lateral intercondylar tubercles.
Attachment Sites in the Intercondylar Region
• Anterior Intercondylar Area:
• Three facets:
• Anterior facet: Attachment of anterior horn of medial meniscus.
• Posterior facet: Attachment of anterior cruciate ligament (ACL).
• Lateral facet: Attachment of anterior horn of lateral meniscus.
• Posterior Intercondylar Area:
• Three facets:
• Anterior facet: Attachment of posterior horn of lateral meniscus.
• Posteromedial facet: Attachment of posterior horn of medial meniscus.
• Large posterior facet: Attachment of posterior cruciate ligament (PCL).

Tibial Tuberosity
• Location: Palpable inverted triangular area on the anterior tibia,
below the condyles.
• Function: Attachment site for the patellar ligament (continuation of
the quadriceps tendon).

Shaft of the Tibia
• Shape: Triangular in cross-section.
• Surfaces:
• Posterior, Medial, Lateral.
• Borders:
• Anterior Border: Sharp, descends from the tibial tuberosity, continuous with a ridge
extending to the lateral condyle.
• Interosseous Border: Subtle vertical ridge along the lateral aspect, descending from
the region below the fibular head.
• Medial Border: Indistinct superiorly but sharp in the midshaft.

Surfaces and Muscle Attachments
• Medial Surface:
• Smooth, subcutaneous, and palpable along its length.
• Inferior to the tibial tuberosity lies a roughened elevation.
• Muscle Attachments: Sartorius, Gracilis, Semitendinosus.
• Widest superiorly.
• Marked by the soleal line, an oblique ridge for muscle attachment.
• Lateral Surface:
• Smooth and unremarkable.

Proximal End of Fibula
• Location: Lateral bone of the leg
• Function: Does not participate in the knee joint or weight-bearing
• Anatomy:
• Proximal Head: Small, rounded structure
• Neck: Narrow region just below the head
• Shaft: Slender and delicate
• Distal End: Forms the Lateral Malleolus at the ankle

Head and Neck of the Fibula
• Head:
• Globe-shaped expansion at the proximal end
• Facet: Circular facet on the superomedial surface for articulation with the
lateral condyle of the tibia
• Styloid Process: Blunt projection posterolateral to the facet
• Lateral Surface: Large impression for biceps femoris attachment
• Depression: For attachment of the fibular collateral ligament of the knee joint
• Neck:
• Separates the head from the shaft
• Common Fibular Nerve: Lies against the posterolateral aspect of the neck

Shaft of the Fibula
• Borders:
• Anterior Border: Sharp and midshaft, begins from the anterior aspect of the
head
• Posterior Border: Rounded, descends from the styloid process of the head
• Interosseous Border: Located medially, for attachment of the interosseous
membrane
• Surfaces:
• Lateral Surface: Associated with the lateral compartment of the leg
• Posterior Surface: Associated with the posterior compartment of the leg
• Medial Surface: Associated with the anterior compartment of the leg

Knee Joint
Largest synovial joint in the body.
• Consists of two articulations:
• Femur and Tibia: Weight-bearing.
• Patella and Femur: Directs quadriceps femoris pull anteriorly to the tibia, reducing tendon wear.
Key Structures:
• Fibrocartilaginous Menisci:
• Located between femoral condyles and tibia.
• Adapt to changes in articular surface shape during movements.
• Reinforcing Ligaments:
• Collateral ligaments (on each side).
• Cruciate ligaments (interconnect femur and tibia).
Function:
• Primarily a hinge joint allowing flexion and extension.
• Locking mechanism:
• Reduces muscle energy for joint extension during standing.

Articular Surfaces of the Knee Joint
Covered by Hyaline Cartilage for smooth movement.
Major Articular Surfaces:
• Femoral Condyles:
• Surfaces in flexion: Curved or round.
• Surfaces in full extension: Flat.
• Tibial Condyles: Adjacent superior surfaces.
• Femur and Patella:
• V-shaped trench on anterior distal femur.
• Posterior aspect of patella.
Key Features:
• Enclosed within a single articular cavity.
• Includes intraarticular menisci: Positioned between femoral and tibial condyles.

Menisci of the Knee Joint
Fibrocartilaginous, C-shaped structures in the knee joint.
• Two menisci:
• Medial Meniscus:
• Attached to joint capsule and tibial collateral ligament.
• Less mobile due to these attachments.
• Lateral Meniscus:
• Unattached to the capsule, making it more mobile.
• Connected to the tendon of the popliteus muscle.
Key Features:
• Attachments: Both menisci are anchored to facets in the intercondylar region of the tibial
plateau.
• Interconnection: Linked anteriorly by the transverse ligament of the knee.
Function:
• Enhance congruency between femoral and tibial condyles during movement:
• Flexion: Articulates with small, curved surfaces of femoral condyles.
• Extension: Articulates with large, flat surfaces of femoral condyles.

Synovial Membrane of the Knee Joint
• Attachment Points:
• Margins of articular surfaces.
• Superior and inferior outer margins of the menisci.
Key Structures:
• Cruciate Ligaments:
• Outside the articular cavity but enclosed within the fibrous membrane of the joint.
• Attachments:
• Tibia (below).
• Femur (above).
• Reflection Posteriorly:
• Synovial membrane loops around the posterior cruciate ligament.
Anterior Structures:
• Separated from Patellar Ligament:
• By the infrapatellar fat pad.
• Fringed Margin (Alar Fold):
• Projects into the articular cavity.
• Infrapatellar Synovial Fold:
• Midline fold, directed posteriorly.
• Attaches to the margin of the intercondylar fossa of the femur.

Synovial Membrane - Expansions & Bursae
Pouches for Low-Friction Surfaces:
• Subpopliteal Recess:
• Extends posterolaterally between the lateral meniscus and
popliteus tendon.
• Suprapatellar Bursa:
• Continuation of the articular cavity superiorly.
• Located between femur and quadriceps femoris muscle/tendon.
• Attached to the articularis genus muscle.
Other Bursae (Not Communicating with Articular Cavity):
• Prepatellar Bursa:
• Subcutaneous, anterior to the patella.
• Infrapatellar Bursae:
• Deep and subcutaneous sides of the patellar ligament.

Fibrous Membrane of the Knee Joint
Key Features:
• Medial Side:
• Blends with tibial collateral ligament.
• Internal surface attached to the medial meniscus.
• Lateral Side:
• External surface separated from fibular collateral ligament.
• Internal surface not attached to the lateral meniscus.
Reinforcements:
• Anterior:
• Attached to patellar margins.
• Reinforced by tendinous expansions from:
• Vastus lateralis and vastus medialis.
• Merges above with quadriceps femoris tendon and below with patellar ligament.
• Anterolateral:
• Strengthened by iliotibial tract.
• Posteromedial:
• Reinforced by oblique popliteal ligament (extension of semimembranosus
tendon).
Popliteus Muscle Role:
• Tendon passes through an aperture in the posterolateral fibrous
membrane.
• Inserts on the lateral femoral condyle.

Ligaments of the Knee Joint
• Patellar Ligament
• Continuation of the quadriceps femoris tendon.
• Attachments:
• Above: Margins and apex of the patella.
• Below: Tibial tuberosity.
• Collateral Ligaments
• Stabilize the hinge-like motion of the knee.
• Fibular Collateral Ligament (Lateral):
• Cord-like structure.
• Attachments:
• Superiorly: Lateral femoral epicondyle (above
popliteus tendon groove).
• Inferiorly: Depression on the lateral fibular head.
• Bursa: Separates it from the fibrous membrane.
• Tibial Collateral Ligament (Medial):
• Broad and flat structure.
• Attachments:
• Superiorly: Medial femoral epicondyle (below
adductor tubercle).
• Inferiorly: Medial tibial margin (above sartorius,
gracilis, semitendinosus tendons).
• Deep surface anchored to the fibrous membrane.

Cruciate Ligaments of the Knee
• Located in the intercondylar region.
• Connect the femur and tibia.
Anterior Cruciate Ligament (ACL):
• Attachments:
• Anterior intercondylar area of the tibia.
• Posteriorly ascends to lateral wall of femur's intercondylar fossa.
• Function: Prevents anterior displacement of the tibia relative
to the femur.
Posterior Cruciate Ligament (PCL):
• Attachments:
• Posterior intercondylar area of the tibia.
• Anteriorly ascends to medial wall of femur's intercondylar fossa.
• Function: Prevents posterior displacement of the tibia
relative to the femur.
Key Feature:
• ACL crosses laterally to PCL, forming a "cross" in the
sagittal plane.

Locking Mechanism of the Knee Joint
Purpose: Stabilizes the knee during
standing, reducing muscle work.
Key Features:
• Change in Articulating Surfaces:
• Flexion:
• Articulating surfaces are curved and
rounded (posterior femoral condyles).
• Extension:
• Articulating surfaces shift to broad and
flat areas (inferior femoral condyles).
• Result: Increased surface area → Greater
stability.
• Medial Rotation of Femur:
• During extension, the femur medially
rotates on the tibia.
• Effect: Tightens associated ligaments,
locking the joint.

Anatomy of the knee joint
• https://www.youtube.com/watch?v=YmyTa3B-ynQ

Tibiofibular Joint Anatomy
• Joint Type: Synovial
• Movement: Very limited
Location:
• Undersurface of the lateral condyle of the tibia
• Superomedial surface of the head of the fibula
Joint Surfaces:
• Flat and circular
• Allow minimal movement
Capsule Reinforcement:
• Anterior and posterior ligaments

Overview of the Leg Anatomy
The leg is the part of the lower limb between the knee joint and ankle joint.
• Proximal: Major structures pass through or near the popliteal fossa behind the knee.
• Distal: Structures pass mainly through the tarsal tunnel on the posteromedial side of the ankle.
• Exceptions: Anterior tibial artery and deep/superficial fibular nerves enter the foot anterior to the ankle.
Bones of the Leg
• Tibia:
• Weight-bearing bone, larger than fibula.
• Forms the knee joint proximally and the medial malleolus distally.
• Articulates with the foot at the ankle joint.
• Fibula:
• Smaller bone on the lateral side of the leg.
• Articulates with the tibia at the superior end but does not form the knee joint.
• Distal end forms the lateral malleolus and is anchored to the tibia by a fibrous joint.

Compartments and Function of the Leg
• Leg Compartments:
• Anterior (Extensor): Dorsiflexes the ankle, extends toes, inverts the foot.
• Posterior (Flexor): Plantarflexes the ankle, flexes toes, inverts the foot.
• Lateral (Fibular): Everts the foot.
• Divisions:
• Interosseous Membrane: Links the tibia and fibula.
• Intermuscular Septa: Pass between the fibula and deep fascia.
• Deep Fascia Attachment: Attaches to the periosteum of the tibia.
• Major Nerves/Vessels: Supply or pass through each compartment.

Shaft of the Tibia
Shape: Triangular cross-section.
• Borders:
• Anterior and Medial Borders: Subcutaneous, easily palpable.
• Interosseous Border: Connected to the fibula via the interosseous membrane.
• Posterior Surface: Marked by the Soleal Line.
• Soleal Line:
• Descends obliquely from the lateral to the medial side.
• Merges with the medial border at the lower part of the tibia.
• Additional Line: A vertical line descending from the midpoint of the soleal line, disappearing in
the lower third of the tibia.
Function and Expansion of the Tibia
• Support: The shaft expands at both ends to support body weight at the knee and ankle joints.
• Upper End: Part of the knee joint.
• Lower End: Part of the ankle joint

Distal End of the Tibia
• Shape: Rectangular box-like structure.
• Medial Malleolus: Bony protuberance on the medial side.
• Articulations:
• The upper part is continuous with the tibia shaft.
• The lower surface and medial malleolus articulate with the talus to form part of the
ankle joint.
• Vertical groove continuing onto the medial malleolus for the tibialis posterior
tendon.
• Lateral Surface:
• Contains a fibular notch, where the distal fibula is anchored via the interosseous
membrane.

Shaft of the Fibula
• Function: The fibula is not involved in weight-bearing.
• Shape: Narrower than the tibia.
• Muscle Enclosure: Except for the ends, the fibula is enclosed by muscles.
• Cross-Section: Triangular shape with three borders and surfaces for muscle,
intermuscular septa, and ligament attachment.
Borders:
• Interosseous Border: Faces and is attached to the tibia by the interosseous membrane.
• Anterior and Posterior Borders: Serve as attachment points for intermuscular septa.
Surfaces:
• Medial Surface: Faces the anterior compartment of the leg.
• Lateral Surface: Faces the lateral compartment of the leg.
• Posterior Surface: Faces the posterior compartment of the leg.
• Posterior Surface Feature: Vertical crest (medial crest) dividing the surface for
attachment of flexor muscles.

Distal End of the Fibula
• Expansion: The distal end expands to form the lateral malleolus.
Lateral Malleolus:
• Medial Surface: Bears a facet for articulation with the talus.
• Forms the lateral part of the ankle joint.
Triangular Area: Just superior to the facet, fits into the fibular notch on the distal tibia, where the tibia
and fibula are joined by the distal interosseous membrane.
Malleolar Fossa: Located posteriorly, for the attachment of the posterior talofibular ligament.
Tendon Grooves and Features of the Lateral Malleolus
• Posterior Surface of the Lateral Malleolus:
• Marked by a shallow groove for the tendons of the fibularis longus and fibularis brevis muscles.
• Function of the Groove: Allows the tendons to pass along the posterior aspect of the lateral
malleolus.

Interosseous Membrane of the Leg
• Function:
• A tough fibrous sheet connecting the tibia and fibula.
• Provides an increased surface area for muscle attachment.
• Structure:
• Collagen Fibers: Descend obliquely from the tibia to the fibula, except at the superior part where
a ligamentous band ascends from tibia to fibula.
• Two Apertures: Located at the top and bottom for vessels to pass between the anterior and
posterior compartments of the leg.
• Distal End:
• The distal ends of the tibia and fibula are held together by the inferior aspect of the interosseous
membrane.
• Reinforced by: Anterior and posterior tibiofibular ligaments.
• Purpose: Forms a solid framework for articulation with the foot at the ankle joint.

Foot Anatomy Overview
The foot is the region of the lower limb distal to the ankle joint, subdivided into:
• Ankle
• Metatarsus
• Digits
Digits:
• Five digits:
• Great toe (Digit I): Medial position
• Little toe (Digit V): Lateral position
Surfaces:
• Superior surface: Dorsum of foot Inferior surface: Sole
Movements:
• Abduction & Adduction: Defined with respect to the long axis of second digit
Key Functions:
• Provides a stable platform for upright stance
• Acts as a lever for forward movement during walking

Bones of the Foot
Three Groups of Bones (Fig. 6.96):
• Tarsal Bones (7)
• Form the skeletal framework of the ankle.
• Metatarsals (I to V)
• Bones of the metatarsus.
• Phalanges
• Bones of the toes:
• Three phalanges per toe, except:
• Great toe (Digit I) has two phalanges.

Foot Bones Anatomy Mnemonic: Tarsals,
Metatarsals, Phalanges
• https://www.youtube.com/watch?v=lJiyv-BOwfI

Tarsal Bones Overview
• Arrangement:
• Divided into proximal and distal groups, with an intermediate bone on the medial side of the
foot.
Proximal Group
• Talus
• Most superior bone of the foot.
• Supported by the calcaneus.
• Articulations:
• Above: Tibia and fibula (forms the ankle joint).
• Forward: Navicular (medial side).
• Calcaneus
• Largest tarsal bone.
• Forms the heel (posterior framework).
• Articulations:
• Forward: Cuboid (lateral side).

Overview of the Talus
Shape & Structure:
• Snail-shaped when viewed from medial or lateral sides
• Key parts:
• Head: Rounded, projects forward and medially.
• Neck: Short, broad, connects to the expanded body.
• Body: Expanded posterior part of the talus.
Articulations:
• Anteriorly: Head articulates with the navicular bone (domed surface fits into circular depression).
• Inferiorly:
• Anterior & middle facets: Articulate with the calcaneus.
• Medial facet: Articulates with the plantar calcaneonavicular ligament (spring ligament).
Sulcus Tali:
• Deep groove passing obliquely forward from medial to lateral.
• Expands dramatically on the lateral side.
• Located posterior to the sulcus tali:
• Posterior calcaneal surface: Large facet for articulation with the calcaneus.

Features
Inferior Surface:
• Features a large oval concave facet (posterior calcaneal articular facet) for articulation with the calcaneus.
Superior Aspect:
• Elevated to fit the socket formed by tibia and fibula at the ankle joint.
• Articulations:
• Upper (trochlear) surface: Articulates with the inferior tibia.
• Medial surface: Articulates with the medial malleolus (tibia).
• Lateral surface: Articulates with the lateral malleolus (fibula).
Lateral Features:
• Lateral process: Bony projection supporting the fibular facet.
• Larger lateral articular surface: Reflects the size of the lateral malleolus.
Posterior Features
• Posterior Process:
• Faces backward and medially.
• Marked by:
• Lateral tubercle
• Medial tubercle
• Flexor Hallucis Longus Groove:
• Between the tubercles, accommodates the flexor hallucis longus tendon as it transitions into the foot.

Overview of the Calcaneus
General Description:
• Largest bone in the foot.
• Shape: Elongate, irregular, box-shaped bone.
• Supports the talus and forms the skeletal framework of the heel.
• Orientation: Long axis along the midline of the foot but deviates laterally anteriorly.
Posterior Region:
• Divided into three parts:
• Upper part: Separated from the calcaneal tendon (Achilles tendon) by a bursa.
• Middle part: Site of Achilles tendon attachment.
• Lower part: Weight-bearing region, continuous with the calcaneal tuberosity on the plantar
surface.

Plantar Surface of the Calcaneus
Calcaneal Tuberosity:
• Projects forward on the plantar surface.
• Features:
• Medial process: Large.
• Lateral process: Small.
• Separated by a V-shaped notch.
Calcaneal Tubercle:
• Located at the anterior end of the plantar surface.
• Attachment site for the short plantar ligament.

Lateral & Medial Surfaces of the Calcaneus
Lateral Surface of the Calcaneus
• Smooth Contour with Two Raised Regions:
• Fibular Trochlea (Peroneal Tubercle):
• Located anterior to the middle of the surface.
• Two shallow grooves for the fibularis brevis and longus tendons.
• Second Tubercle:
• Located superior and posterior to the fibular trochlea.
• Attachment for the calcaneofibular ligament of the lateral collateral ligament.
Medial Surface and the Sustentaculum Tali
• Concave Surface:
• Prominent feature: Sustentaculum tali (bony shelf).
• Supports the posterior part of the talus head.
• Key Structures:
• Groove under the sustentaculum tali for the flexor hallucis longus tendon.
• Superior surface of the sustentaculum tali:
• Middle talar articular surface: Articulates with the talus.

Superior Surface of the Calcaneus & Tarsal Sinus
Superior Surface of the Calcaneus
• Talar Articular Surfaces:
• Anterior talar articular surface:
• Small, articulates with the anterior facet of the talus head.
• Middle talar articular surface:
• On the sustentaculum tali.
• Posterior talar articular surface:
• Large, near the middle of the calcaneus, articulates with the talus body.
• Calcaneal Sulcus:
• Deep groove between the posterior and anterior articular surfaces.
• Combines with the sulcus tali of the talus to form the tarsal sinus.
Tarsal Sinus
• Definition:
• Large gap between the anterior ends of the calcaneus and talus.
• Visible from the lateral aspect of the foot.
• Formed By:
• Calcaneal sulcus (on the calcaneus).
• Sulcus tali (on the talus).

Intermediate tarsal bone(Navicular)
Location and Articulations:
• Posteriorly (behind): Articulates with the talus.
• Anteriorly (in front): Articulates with the distal tarsal bones, which include the
three cuneiform bones (medial, intermediate, and lateral).
• Laterally: May articulate with the cuboid bone in some individuals.
Distinguishing Feature:
• The navicular tuberosity, a prominent rounded projection on the medial side of
the bone, is a key feature.
• It serves as the attachment point for the tibialis posterior tendon, a crucial muscle
for maintaining the medial longitudinal arch of the foot.

Distal Group of Tarsal Bones
Lateral to Medial:
• Cuboid (Cube-shaped):
• Articulations:
• Posterior: Calcaneus
• Medial: Lateral cuneiform
• Anterior: Bases of the 4th and 5th metatarsals
• Key Feature:
• Prominent groove on the anterior plantar surface for the fibularis longus tendon, passing
obliquely forward (lateral to medial).
Three Cuneiforms (Wedge-shaped):
• Lateral, Intermediate, and Medial cuneiforms.
• Articulations:
• Posterior: Navicular
• Anterior: Bases of the 1st, 2nd, and 3rd metatarsals
• With each other (medial to lateral).

Metatarsals of the Foot
Key Features:
• Five metatarsals: Numbered I to V, from medial to lateral.
• Metatarsal I (Great toe):
• Shortest and thickest.
• Plantar surface of its head articulates with two sesamoid bones.
• Metatarsal II: Longest.
• Each metatarsal has:
• Base (proximal end):
• Articulates with distal tarsal bones.
• Bases of II–V also articulate with each other.
• Shaft (middle).
• Head (distal end):
• Articulates with the proximal phalanx of the toe.

Phalanges of the Foot
Key Features:
• Bones of the toes:
• Three phalanges per toe (proximal, middle, distal) except the great toe, which has only two (proximal and
distal).
Structure of Each Phalanx:
• Base (proximal):
• Proximal phalanx base articulates with the head of the related metatarsal.
• Shaft (middle):
• Elongated and slender.
• Head (distal):
• Distal phalanx head is nonarticular and flattened into a crescent-shaped plantar tuberosity, located under
the plantar pad at the tip of the toe.
Special Notes:
• Combined length of all phalanges in each toe is shorter than the associated metatarsal.

Ankle Joint: Anatomy and Structure
• Type: Synovial joint
Bones Involved:
• Talus of the foot
• Tibia and Fibula of the leg
• Key Features:
Motion: Hinge-like dorsiflexion and plantarflexion.
Socket Formation (Bracket-shaped):
• Roof: Inferior surface of the distal tibia.
• Medial Side: Medial malleolus of the tibia.
• Lateral Side: Lateral malleolus of the fibula.
Articular Surfaces:
• Covered by hyaline cartilage.
Talus shape:
• Resembles a half-cylinder, with the upper curved surface and ends fitting the socket.
• Wider anteriorly, leading to better stability during dorsiflexion.

Ankle Joint: Stability and Ligaments
Joint Stability:
• Most stable during dorsiflexion (wider part of the talus fits tightly into the socket).
• Less stable during plantarflexion (narrower part of the talus in the joint).
Stabilizing Structures:
• Synovial Membrane:
• Encloses the joint cavity.
• Attaches around margins of articular surfaces.
• Fibrous Membrane:
• Covers the synovial membrane.
• Attaches to adjacent bones.
Ligaments:
• Medial Ligament (Deltoid): Provides stability on the medial side.
• Lateral Ligaments: Stabilize the lateral side of the joint.

Medial Ligament (Deltoid Ligament)
• Large, strong, triangular ligament.
• Apex: Attached to the medial malleolus.
• Base: Extends from the tuberosity of the navicular (front) to the medial
tubercle of the talus (back).
Subdivisions (4 Parts):
• Tibionavicular Part:
• Attaches to:
• Tuberosity of the navicular.
• Margin of the plantar calcaneonavicular ligament (spring ligament).
• Connects the navicular to the sustentaculum tali of the calcaneus.
• Tibiocalcaneal Part (Central):
• Attaches to the sustentaculum tali of the calcaneus.
• Posterior Tibiotalar Part:
• Attaches to the medial side and medial tubercle of the talus.
• Anterior Tibiotalar Part:
• Lies deep to the tibionavicular and tibiocalcaneal parts.
• Attaches to the medial surface of the talus.

Lateral Ligament of the Ankle
• Anterior Talofibular Ligament:
• Short ligament.
• Attaches from the anterior margin of the lateral
malleolus to the adjacent region of the talus.
• Posterior Talofibular Ligament:
• Runs horizontally backward and medially.
• Attaches from the malleolar fossa on the medial
side of the lateral malleolus to the posterior process
of the talus.
• Calcaneofibular Ligament:
• Attaches above to the malleolar fossa on the
posteromedial side of the lateral malleolus.
• Passes posteroinferiorly to attach below to a
tubercle on the lateral surface of the calcaneus.

Intertarsal Joints
Functions:
• Inversion: Turning the sole of the foot inward.
• Eversion: Turning the sole of the foot outward.
• Pronation: Rotating the front of the foot laterally relative to the back of the foot.
• Supination: The reverse of pronation, rotating the front of the foot medially.
Importance:
• Pronation and supination allow the foot to maintain normal contact with the ground when in different
stances or standing on irregular surfaces.
Major Joints Involved:
• Subtalar Joint
• Talocalcaneonavicular Joint
• Calcaneocuboid Joint
• Together, the talocalcaneonavicular and calcaneocuboid joints form the transverse tarsal joint.
• Other Joints:
• Joints between the cuneiforms and between the cuneiforms and navicular allow limited movement.
• The joint between the cuboid and navicular is usually fibrous.

Subtalar Joint
• Location:
• Between the large posterior calcaneal facet on the inferior surface
of the talus and the corresponding posterior talar facet on the
superior surface of the calcaneus.
• Structure:
• The articular cavity is enclosed by a synovial membrane, covered by
a fibrous membrane.
Functions:
• Allows gliding and rotation movements, contributing to inversion
and eversion of the foot.
Stabilizing Ligaments:
• Lateral Talocalcaneal Ligament
• Medial Talocalcaneal Ligament
• Posterior Talocalcaneal Ligament
• Interosseous Talocalcaneal Ligament (located in the tarsal sinus).

Talocalcaneonavicular Joint
Location & Structure:
• The head of the talus articulates with the calcaneus, plantar calcaneonavicular ligament (spring
ligament), and navicular.
Facets:
• Anterior and middle calcaneal facets on the inferior surface of the talar head.
• Anterior and middle talar facets on the superior surface and sustentaculum tali of the calcaneus.
• The part of the joint between the talus and the plantar calcaneonavicular ligament (spring
ligament) is between the ligament and the medial facet on the inferior surface of the talar head.
• The joint between the navicular and talus is the largest component, located between the ovoid
anterior end of the talar head and the concave posterior surface of the navicular.
Functions:
• Allows gliding and rotation movements.
• Involved in inversion, eversion, pronation, and supination of the foot.

Ligaments of the Talocalcaneonavicular Joint
• Capsule Reinforcements:
• Posteriorly: Interosseous talocalcaneal ligament.
• Superiorly: Talonavicular ligament (between the neck of the talus and adjacent regions of the
navicular).
• Inferiorly: Plantar calcaneonavicular ligament (spring ligament).
• Lateral Reinforcement:
• Calcaneonavicular part of the bifurcate ligament: Y-shaped ligament located superior to the joint.
• Base: Attached to the anterior aspect of the superior surface of the calcaneus.
• Arms:
• Calcaneocuboid ligament: Attached to the dorsomedial surface of the cuboid.
• Calcaneonavicular ligament: Attached to the dorsolateral part of the navicular.
• Plantar Calcaneonavicular Ligament (Spring Ligament):
• Broad, thick ligament that spans between the sustentaculum tali (behind) and the navicular (in
front).
• Supports the head of the talus and resists the depression of the medial arch of the foot.

Calcaneocuboid Joint and Ligaments
• Type: Synovial joint
• Articulating Surfaces:
• Anterior facet of the calcaneus.
• Posterior facet of the cuboid.
Movements:
• Sliding and rotating movements.
• Involved in inversion and eversion of the foot.
• Contributes to pronation and supination of the forefoot on the hindfoot.
Reinforcing Ligaments:
• Bifurcate Ligament: Supports the lateral part of the joint.
• Plantar Calcaneocuboid Ligament (Short Plantar Ligament):
• Structure: Short, wide, and strong.
• Attachment: Connects the calcaneal tubercle to the inferior surface of the cuboid.
• Function: Supports the calcaneocuboid joint and assists the long plantar ligament in resisting depression of the lateral arch.
• Long Plantar Ligament:
• Structure: Longest ligament in the sole of the foot.
• Attachment:
• Posteriorly: From the inferior surface of the calcaneus.
• Anteriorly: To a ridge and tubercle on the inferior surface of the cuboid.
• Function: Supports the calcaneocuboid joint, resists depression of the lateral arch, and extends to the bases of the metatarsal
bones.

Tarsometatarsal and Metatarsophalangeal Joints
Tarsometatarsal Joints:
• Type: Plane joints
• Movements:
• Limited sliding movements.
• Great toe and medial cuneiform joint: Greater range of movement allowing flexion, extension, and rotation.
• Role:
• Contribute to pronation and supination of the foot.
• Work with the transverse tarsal joint in foot rotation.
Metatarsophalangeal Joints:
• Type: Ellipsoid synovial joints
• Articulating Surfaces:
• Heads of metatarsals with the bases of the proximal phalanges.
• Movements:
• Extension and flexion.
• Limited abduction, adduction, rotation, and circumduction.
• Reinforcements:
• Medial and lateral collateral ligaments.
• Plantar ligaments with grooves for the long tendons of the digits.

Deep Transverse Metatarsal Ligaments & Interphalangeal Joints
Deep Transverse Metatarsal Ligaments:
• Structure: Four ligaments linking the heads of the metatarsals.
• Function:
• Enable the metatarsals to function as a unified structure.
• Blend with the plantar ligaments of the adjacent metatarsophalangeal joints.
• Special Note:
• The metatarsal of the great toe is linked to the second toe by a deep transverse metatarsal ligament.
• The great toe has a limited range of motion and a restricted independent function, unlike the thumb in the
hand.
Interphalangeal Joints:
• Type: Hinge joints
• Movements: Mainly flexion and extension.
• Reinforcements:
• Medial and lateral collateral ligaments.
• Plantar ligaments.

Tarsal Tunnel, Retinacula, and Major Structures at the Ankle
Tarsal Tunnel:
• Formed on the posteromedial side of the ankle by:
• Medial malleolus of the tibia.
• Medial and posterior surfaces of the talus.
• Medial surface of the calcaneus.
• Inferior surface of the sustentaculum tali of the calcaneus.
• Overlain by the flexor retinaculum.
• Flexor Retinaculum:
• Structure: Strap-like layer of connective tissue.
• Attachment:
• Above: Medial malleolus.
• Below: Inferomedial margin of the calcaneus.
• Continuous with the deep fascia of the leg and foot.
• Forms compartments for tendons of the flexor muscles.
Major Structures in the Tunnel:
• Tendons:
• Tibialis posterior (medial).
• Flexor digitorum longus.
• Flexor hallucis longus.
• Vessels and Nerve:
• Posterior tibial artery, veins, and tibial nerve pass through.
• Pulse of posterior tibial artery felt midway between malleolus and calcaneus.

Arches of the Foot
Purpose: The arches absorb and
distribute downward forces during
standing and movement.
• Longitudinal Arch:
• Formed between the posterior calcaneus
and the heads of the metatarsals.
• Highest on the medial side and lowest on
the lateral side.
• Divided into medial and lateral parts.
• Transverse Arch:
• Located at the head of the talus in the
coronal plane.
• Disappears near the heads of the
metatarsals, where bones are held by
deep transverse metatarsal ligaments.

In the clinic
Collateral Ligament Injuries
• The collateral ligaments are important for keeping the knee stable and
controlling sideways movement. There are two main ligaments:
• Fibular Collateral Ligament (Lateral Side):
• Injured by a varus force (pushing the knee outward).
• Less commonly injured compared to the tibial collateral ligament.
• Tibial Collateral Ligament (Medial Side):
• Injured by a valgus force (pushing the knee inward).
• Can be part of the "unhappy triad":
• Tear of the tibial collateral ligament.
• Tear of the medial meniscus.
• Tear of the anterior cruciate ligament (ACL).

Cruciate Ligament Injuries
• Anterior Cruciate Ligament (ACL) Injuries
• Common Causes:
• Sudden changes in movement direction (cutting or pivoting).
• Twisting, overextending the knee, or direct collisions (common in sports).
• What Happens:
• The ACL fibers may tear completely or partially.
• A sudden "pop" or "click" is often felt, followed by swelling and pain.
• Symptoms:
• Instability in the knee.
• Difficulty with activities that involve quick movements or turning.
• Treatment:
• Active lifestyle (e.g., athletes): Surgery to reconstruct the ligament.
• Less active lifestyle: Knee braces and physical therapy may help, but long-term damage could lead to early arthritis.
• Posterior Cruciate Ligament (PCL) Injuries
• Common Causes:
• Significant force, like hitting the knee on a dashboard in a car crash.
• Overextension of the knee.
• What Happens:
• The tibia (shin bone) moves backward relative to the thigh bone (tibial sag sign).
• Symptoms:
• Pain, swelling, and difficulty walking or bearing weight.
• Treatment:
• Depends on the severity (sprain, partial, or full tear):
• Mild cases: Rest, braces, and physical therapy.
• Severe cases: Surgery, especially for active individuals.

What is Osteoarthritis?
• A degenerative joint disease affecting synovial joints.
• Involves damage to cartilage and bone, leading to:
• Pain
• Stiffness
• Limited Movement
• Key Changes in the Joint:
• Cartilage Damage: Cushion between bones wears away.
• Joint Space Reduction: Bones move closer.
• Bony Changes:
• Sclerosis: Hardening of bones.
• Osteophytes: Small bony outgrowths.
• Cysts: Fluid-filled spaces in the bone.
• Malalignment: Crooked joints over time.
• Commonly Affected Joints:
• Hands and Wrists (small joints).
• Lower Limbs: Hips, knees, and feet.

Osteoarthritis - Symptoms & Treatment
Symptoms:
• Pain: Worse after activity or in the morning.
• Stiffness: Hard to move the joint.
• Limited Mobility: Movement becomes restricted.
Who’s at Risk?
• Age: Increases with age (men earlier than women).
• Genetics: Family history.
• Joint Overuse or Trauma: Sports injuries or repetitive motion.
• Other Causes: Poor nutrition, metabolic problems.
• Treatment Options:
• Early Stage:
• Lifestyle changes to avoid pain.
• Simple pain relief medications.
• Advanced Stage:
• Joint Replacement Surgery: Effective but has risks (e.g., infection, implant failure).

Bunions
• Definition: A bunion is a bony bump on the
medial (inner) side of the first
metatarsophalangeal joint (big toe joint).
• Cause:
• Abnormal stresses on the joint.
• Common in people who wear high heels or pointed
shoes.
• Can also be influenced by osteoporosis or a
hereditary predisposition.
• Symptoms:
• Pain, swelling, and inflammation.
• The big toe moves toward smaller toes, causing
crowding.
• Treatment:
• Non-surgical: Padding shoes, changing footwear,
and anti-inflammatory drugs.
• Surgery: In severe cases, surgery may be needed to
realign the toe.

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